Bankrupt wireless communications firm LightSquared Inc. has filed a lawsuit accusing Dish Network Corp. and its chairman, Charles Ergen, of improperly trying to take control of LightSquared's broadband spectrum, Reuters reported yesterday. The lawsuit, filed in bankruptcy court on Friday, is an effort to revive an earlier case by LightSquared's controlling stakeholder, Phil Falcone's Harbinger Capital Partners, that was thrown out last month. LightSquared alleges that Dish, Ergen, and other Ergen-controlled entities made improper trades and violated a key credit agreement in order to become LightSquared's largest creditor, with the intention of taking control of LightSquared's spectrum, the airwaves used for wireless communications.